Enable writes after failover

Praefect now sets nodes to read-only after a failure, so we have to
enable writes before we can push.

qa/qa/service/praefect_manager.rb

@@ -13,6 +13,10 @@ module QA
         @secondary_node = @second_node
       end
 
+      def enable_writes
+        shell "docker exec praefect bash -c '/opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml enable-writes -virtual-storage default'"
+      end
+
       def stop_primary_node
         shell "docker stop #{@primary_node}"
         @secondary_node, @primary_node = @primary_node, @secondary_node

qa/qa/specs/features/browser_ui/3_create/gitaly/high_availability_spec.rb

@@ -10,7 +10,7 @@ module QA
           end
         end
         let(:initial_file) { 'pushed_to_primary.txt' }
-        let(:final_file) { 'pushed_to_secondary.txt' }
+        let(:final_file) { 'committed_to_primary.txt' }
         let(:praefect_manager) { Service::PraefectManager.new }
 
         before do
@@ -41,11 +41,13 @@ module QA
             expect(show).to have_file(initial_file)
           end
 
+          praefect_manager.enable_writes
+
           Resource::Repository::Commit.fabricate_via_api! do |commit|
             commit.project = project
             commit.add_files([
               {
-                file_path: 'committed_to_primary.txt',
+                file_path: final_file,
                 content: 'This should exist on both nodes too'
               }
             ])